Vehicle stability is an important consideration in vehicle design. When driver intervention is insufficient, safety can be improved by the addition of vehicle stability control (VSC). Typical vehicle stability controllers are designed using a linearized vehicle model and an assumed set of parameters. However, some parameters like mass and inertial properties may not be constant between operations. To recover controller performance in the presence of unknown parameters, adaptive estimates can be developed. This thesis seeks to implement a model reference adaptive controller for yaw rate and side slip control and to evaluate any implementation issues that may arise. A linearized vehicle model is used for controller design via a Lyapunov approach and a combined front wheel steering (FWS) and direct yaw control (DYC) controller is developed. The combined FWS+DYC controller is tested in a low friction double lane change with initial parameter estimation error. The FWS+DYC controller was found to be robust to parameter changes, and the adaptive parameter estimates did not provide any noticeable improvement over the non-adaptive case. A four wheel steering (4WS) controller is developed by a similar approach and tested under the same conditions. Both controllers were found to be effective at stabilizing the vehicle. An unexpected finding was that though the combined FWS+DYC controller was effective even in low friction conditions with parameter errors, the required motor torque was very large and oscillated rapidly. This was diminished through the addition of a low pass filter on the controller yaw moment output, but could not be removed entirely. / text

O principal propósito deste trabalho é desenvolver e caracterizar o veículo robótico ℏelvis III, para ser usado no desenvolvimento de pesquisas na área de controle e navegação de robôs móveis. O sistema de propulsão foi caracterizado para determinar a velocidade real do veículo em quatro tipos diferentes de terrenos (Asfalto, grama, grama-terra e terra). Também foi caracterizado o sistema de esterçamento mediante o modelo cinemático da bicicleta, onde se obteve a relação entre a posição do servo motor encarregado do esterçamento do veículo e o valor do ângulo de esterçamento de uma bicicleta. Foram determinados os valores dos erros CEP (Circular Error Probability) e SEP (Spherical Error Probability) do GPS (Global Positioning System) embarcado no veículo mediante dois testes: um em São Carlos – SP (Brasil) e outro em Villavicencio – Meta (Colômbia). Nesses testes foi caracterizada a IMU (Inertial Measurement Unit) embarcada no veículo, além de verificado o efeito da luz solar no funcionamento do sensor tipo LIDAR (Laser Imaging Detection and Ranging) embarcado no helvis III. Por último, pode-se definir a dinâmica do veículo à frente, com a determinação seu centro de massa, e é apresentado o comportamento das forças sob as rodas quando o veículo fica parado ou em movimento sobre terrenos que geram uma inclinação em algum dos eixos cartesianos. / The main objective of this work is the development and characterization of a robotic vehicle ℏelvis III in order to use it in the development of researches focused on the fields of mobile robotics control and navigation. Initially the propulsion system was characterized in order to determine the real velocity of vehicle in real conditions (four different kinds of grounds were used). In addition to this, the steering system was also characterized by applying the well-known bicycle kinematic model. During these experimental tests we could find the relation between the position of the servo-motor and the value of steering angle of the bicycle model. The real values of CEP (Circular Error Probability) and SEP (Spherical Error Probability) errors of the vehicle embedded GPS (Global Positioning System) were determined based on two experiments: the first one was carried out in São Carlos – SP (Brazil) and the second one in Villavicencio – Meta (Colombia). During the GPS experiments we could also characterize the vehicle embedded IMU (Inertial Measurement Unit). Then we could observe and measure the effect of solar light on the LIDAR sensor (Laser Imaging Detection and Ranging) performance. Finally, the forward vehicle dynamics is described, with the determination of the center of mass of the vehicle and the observation of the normal forces behavior in the vehicle wheels when it is stopped or moved on an inclined floor.

The Wu-Luo River located in the Ping-Tong County of southern Taiwan has long been polluted by untreated domestic and partially treated poultry wastewaters and is among the most polluted rivers in Taiwan. A full-scale constructed wetland (CW) has been in operation since January of 2005 for cleaning a part of the polluted river water. The purpose of this study was to investigate the specifications of the CW and its performance for removing both organic and inorganic pollutants form the influent water. Results indicate that during the investigation period of April 2006 to February 2007, the CW had channel widths of 86-112 m (average 100 m) and a zone-type length of 1,600 m. It occupied a total area of 18 hectares in which around 9 hectares were wetted by the introduced river water. Around 4.7 hectares of the CW was flooded by the river water and 1.9 hectares were occupied by emergent and floating plants such as cattail, water lettuce, reed, water celery, and bara grass. A total water volume of around 6,800 m3 was estimated. In the period, 10,000-20,000 m3/day (CMD) (average 10,800 CMD) of the polluted river water was introduced to the CW and a hydraulic retention time (HRT) of 0.63 day was estimated for the flowing water in the through the water body. Results also indicated that the influent water has the following qualities (unit in mg/L except pH and number in parentheses indicates the average value): total COD (CODt) 10-121 (52), BOD 6-36 (21), suspended solids (SS) 10-165 (70), pH 5.4-8.1 (7.4), ammonia-N 2-22 V (13), nitrate-N 0-9.4 (2.5), nitrite-N 0-1.8 (0.2), total-N (TN) 9.9-41.3 (22.6), phosphate-P 0-3.1 (0.9), total-P (TP) 1.2-36.7 (5.2), Cu 0.022-0.60 (0.071), and Zn 0.01-0.36 (0.13). It was found that water sampled from nearly the middle point of the CW got better clarification results than that from the effluent end. Pollutant removal efficacies were 60, 60, and 67%, respectively, for CODt, BOD, and SS at the middle point, while 56, 54, and 45%, respectively, for CODt, BOD, and SS at the effluent end. Organics, N, and P released from rotten plants were responsible for the poor water qualities at the end. The CW had only a TN removal efficacy of around 18% and no TP removal effect.

O principal propósito deste trabalho é desenvolver e caracterizar o veículo robótico ℏelvis III, para ser usado no desenvolvimento de pesquisas na área de controle e navegação de robôs móveis. O sistema de propulsão foi caracterizado para determinar a velocidade real do veículo em quatro tipos diferentes de terrenos (Asfalto, grama, grama-terra e terra). Também foi caracterizado o sistema de esterçamento mediante o modelo cinemático da bicicleta, onde se obteve a relação entre a posição do servo motor encarregado do esterçamento do veículo e o valor do ângulo de esterçamento de uma bicicleta. Foram determinados os valores dos erros CEP (Circular Error Probability) e SEP (Spherical Error Probability) do GPS (Global Positioning System) embarcado no veículo mediante dois testes: um em São Carlos – SP (Brasil) e outro em Villavicencio – Meta (Colômbia). Nesses testes foi caracterizada a IMU (Inertial Measurement Unit) embarcada no veículo, além de verificado o efeito da luz solar no funcionamento do sensor tipo LIDAR (Laser Imaging Detection and Ranging) embarcado no helvis III. Por último, pode-se definir a dinâmica do veículo à frente, com a determinação seu centro de massa, e é apresentado o comportamento das forças sob as rodas quando o veículo fica parado ou em movimento sobre terrenos que geram uma inclinação em algum dos eixos cartesianos. / The main objective of this work is the development and characterization of a robotic vehicle ℏelvis III in order to use it in the development of researches focused on the fields of mobile robotics control and navigation. Initially the propulsion system was characterized in order to determine the real velocity of vehicle in real conditions (four different kinds of grounds were used). In addition to this, the steering system was also characterized by applying the well-known bicycle kinematic model. During these experimental tests we could find the relation between the position of the servo-motor and the value of steering angle of the bicycle model. The real values of CEP (Circular Error Probability) and SEP (Spherical Error Probability) errors of the vehicle embedded GPS (Global Positioning System) were determined based on two experiments: the first one was carried out in São Carlos – SP (Brazil) and the second one in Villavicencio – Meta (Colombia). During the GPS experiments we could also characterize the vehicle embedded IMU (Inertial Measurement Unit). Then we could observe and measure the effect of solar light on the LIDAR sensor (Laser Imaging Detection and Ranging) performance. Finally, the forward vehicle dynamics is described, with the determination of the center of mass of the vehicle and the observation of the normal forces behavior in the vehicle wheels when it is stopped or moved on an inclined floor.

Résumé: Les lacs occupent environ 30% du territoire dans le nord du Canada. Ils peuvent avoir d’importants impacts sur le climat qui ont un effet par la suite sur les propriétés thermiques des lacs. L’étude d’un lac doit généralement débuter avec un bilan calorifique de la surface. La différentiation précise que l’énergie disponible en flux de chaleur sensible ou latent est un élément crucial pour la compréhension des interactions entre les processus climatiques à une échelle régionale. Dans cette étude, le flux de chaleur sensible et le ratio de Bowen sont obtenus à partir des données de la télédétection. La méthodologie se base sur l’utilisation de données microondes (SMM/I) afin de calculer la température de la surface du sol avec la méthode de Fily et al. (2003) et Mialon et al. (2007). La caractérisation de la surface du sol est effectuée à partir de données satellitaires optiques (capteurs SPOT & VGT). Les paramètres météorologiques utilisés pour estimer les flux proviennent de la base de données du North American Regional Reanalysis (NARR). Les résultats présentent un portrait quotidien, mensuel et saisonnier de l’énergie sensible à l’interface sol-air par rapport à la fraction de la surface de plan d’eau (FWS). Nous comparons ensuite nos résultats avec les flux du modèle NARR et quelques mesures in situ. Quatre sites couvrants différents types de surfaces à travers le Canada ont été étudiés pendant les étés 1998 et 2000 (de juin à septembre) : le nord du Québec (toundra), les Territoires du Nord-Ouest (le Grand lac des Esclaves [ou, en anglais, Great Slave Lake. GSLJ et le bassin de la rivière Mackenzie), le Manitoba (zone humide) et le Labrador (taïga). Les résultats montrent que les flux d’énergie sensible satellitaires sont semblables aux flux estimés par le NARR lorsque la FWS est petit (sans lac) ou pour des zones avec de larges surfaces d’eau (Mackenzie Great Slave Lake), mais diffèrent lorsque la FWS augmente à l’intérieur d’un pixel. Ceci signifie que les modèles climatiques régionaux devraient considérer la proposition du territoire occupée par des étendues d’eau. Nous déduisons que les effets de la taille des lacs sont reliés aux conditions environnementales du milieu. Les résultats de la comparaison avec des mesures in situ pour le GSL et la zone humide sont encourageants. Le ratio de Bowen sur le site du bassin de la rivière Mackenzie montre qu’il y a une augmentation de la chaleur sensible durant la deuxième moitié de l’été en comparaison à la première moitié. Il y a ainsi un plus grand stress hydrique pendant la deuxième moitié de l’été. Cependant, il n’y a pas de patrons clairs en comparaison avec le site GSL. La comparaison entre les différents sites indique une variation énergétique annuelle minimale pour la zone humide. || Abstract: Lakes occupy roughly 30% of Canada's northern landscape. They can have important impacts on the climate, and climate modification will affect lake thermal properties. Study of a lake most generally begins with heat budget at its surface. Accurate partitioning of the available energy at the surface into sensible and latent heat flux is crucial to the understanding of interactions between climate processes on a regional scale. In this study, sensible heat flux and the Bowen ratio for the summer period are retrieved using reanalysis and remote sensing data. The methodology is based on the use of microwave data for retrieving land surface temperature (SSM/I) with the method of Fily et al. (2003) and Mialon et al. (2007). The land cover characterization is derived from remotely sensed optical data (SPOT VGT sensor). Some meteorological parameters used for retrieving flux are derived from the North American Regional Reanalysis (NARR) database. The results from this study present a picture of the daily, monthly and seasonally sensible energy over summer period at the land-air interface versus the Fraction of Water Surface (FWS). We compare our results with the NARR model's flux in addition to few in situ measurements. Four sites covering different land cover types across Canada were investigated during the 1998 and 2000 summers (June to September): Northern Quebec (tundra), Northwest Territories (Great Slave Lake, or GSL, and Mackenzie River Basin), Manitoba (wetlands) and Labrador (taiga). The results show that the satellite-derived sensible flux is close to the NARR flux estimate when the fraction of water surface is small (no lakes) and over large open water areas (Mackenzie Great Slave Lake), but differs when the FWS increases within the pixel. This means that regional climate models should take into account lake cover fraction. We infer that effects of the lake-size are closely related to surrounding environmental conditions. The results of the comparison with in situ measurements for Great Slave Lake (1998) and the Wetland site are encouraging. For the Mackenzie River Basin site, the results of the Bowen ratio show that there is an increase of sensible heat partition during the second half of the summer in comparison with the first half, meaning that there is more water stress over the second half of the summer than the first. But for the Wetland site, there is no clear pattern, and in comparison with GSL, temporal variation is less significant. Comparisons between different sites indicate minimum year to year energy variation for the Wetland area.